Microfluidic paper-based analytical devices coupled with coprecipitation enrichment show improved trace analysis of copper ions in water samples

Abstract

The present study was focused on improving sensitivity to trace levels of Cu(II) by subjecting microfluidic paper-based analytical devices (μ-PADs) to a preconcentration process via coprecipitation using aluminum hydroxide. The experimental conditions were optimized for the pH of the coprecipitation, centrifugation, and amounts of reagents that were deposited onto µ-PADs for Cu(II) assay. The resultant limit of detection reached as low as 0.003 mg L -1 with a linear range of 0.01-2.00 mg L -1 . The relative standard deviations for intra-and inter-day precision were 3.2 and 4.6%, respectively (n = 9). Spiked water samples were analyzed using the μ-PADs after coprecipitation preconcentration. The results were verified by comparing them with those of inductively coupled plasma-optical emission spectrometry (ICP-OES).Recoveries ranged from 97.1-104% and from 98.7-105% using the present method and ICP-OES, respectively. These results suggest that the simple, highly sensitive, and inexpensive proposed method would be helpful for analyzing trace levels of Cu(II) in water samples in poorly equipped laboratories.

Recent progress of microfluidic sample preparation techniques

“…Therefore, the target cell can be stained by biochemical reactions and detected by a fluorescence detector in situ. In another case, filter paper of μ‐PAD was pretreated with bathocuproine for coprecipitation enrichment to improve trace copper ions analysis [70]. The bathocuproine in μ‐PAD is a colorimetric reagent to the formation of orange‐red colored Cu(I) when the Cu(II) solution is injected.…”

Trace nickel analysis in water samples via paper-based devices coupled with co-precipitation

“…The μ-PAD design and dimensions are described in Figure 1D, and our previously reported design, dimensions and techniques were used for device fabrication. 29 The pattern of the μ-PADs was drawn using Microsoft Office PowerPoint 2010. The μ-PADs consisted of a sample zone attached to three channels that led to three detection zones for triplicate measurements, and one control zone (Figure 1D).…”

“…Recently, we have demonstrated the assay of Cu ions via combining colourimetric µ-PADs with co-precipitation. 29 In this study, we report an assay of Ni ions using colourimetric µ-PADs coupled with co-precipitation enrichment technique. The co-precipitation enrichment under optimized condition allowed detection of Ni(II) in tap and mineral water samples at trace level lower than the WHO guideline value (0.07 mg L −1 ).…”

Wax screen-based fabrication of paper devices for the determination of iron in particulates of selected welding fumes in Addis Ababa, Ethiopia

“…The conventional instruments are expensive, needs time-consuming sample pre-treatment and skilled personnel for operation. The demand for environmental and worker's safety analysis in an affordable approach necessitates the exploration for sensitive and rapid determination methods for particulate metals [15][16][17][18][19][20][21].…”